Portable generators continue to gain popularity and to be designed to be smaller and lighter to increase their portability. In order to maintain the small and lightweight characteristics, portable generators have onboard or main fuel tanks that are relatively small because carrying onboard fuel can significantly add to the weight of a portable generator. The limited fuel capacity results in a limited runtime of the portable generator. Efforts have been made to provide additional fuel capacity to portable generators by adding stand-alone auxiliary fuel tanks with external fuel lines and ancillary priming bulbs or other devices. Known stand-alone auxiliary fuel tanks require manual manipulation to connect to the fuel system of the portable generator and can be difficult to evaluate fuel level in the stand-alone auxiliary fuel tanks, which can also make accurately planning generator-dependent activities and tank refills difficult. This can be further complicated by some fuel gauges for the onboard or main tanks being susceptible to inaccuracies or failures since some such gauges include paddle-type fuel senders with rheostats that are wetted by fuel that can be compromised if left in reformulated gasoline as fuel for extended periods of time.
It is an object and feature of the present invention to provide a self-connecting auxiliary tank(s) for a portable generator that provides users extended generator runtime without external hoses and manual siphons and that may display a fuel level of the auxiliary tank(s) and/or combined fuel level of the auxiliary tank(s) and a main or onboard tank and/or a remaining runtime for the portable generator.
It is an object and feature of the present invention to provide a system for calculating and displaying an estimated remaining runtime for a portable generator, which may include recalculating the estimated remaining runtime when a tool-less and self-connecting auxiliary tank(s) is connected to the portable generator.
It is an object and feature of the present invention to provide a method that combines load current and fuel gauge or fuel level values to calculate and/or recalculate an estimated remaining runtime value. This may allow users to plan generator-dependent activities and tank refills and may provide a relatively more accurate estimate of remaining runtime than could be obtained from either a fuel gauge alone or a power meter alone.
It is an object and feature of the present invention to provide a self-connecting auxiliary tank(s) for a portable generator that provides users extended generator runtime without external hoses and manual siphons and that may display a fuel level of the auxiliary tank(s) and/or combined fuel level of the auxiliary tank(s) and a main or onboard tank and/or a remaining runtime for the portable generator.
According to one aspect of the invention, a method is provided for calculating and displaying an estimated remaining runtime for a portable generator. The generator has a fuel tank that stores fuel for consumption by an internal combustion engine providing torque that is converted into electrical energy in the generator. An initial runtime estimation is performed by detecting an initial fuel level characteristic of fuel in the fuel tank, such as how much fuel is in the tank. An initial generator load characteristic of load being applied to the generator is detected, such as energy used by an accessory plugged into the generator which may correspond to an energy value such as BTUs (British Thermal Units) used by the generator. An initial estimated remaining runtime value is calculated that corresponds to a time duration at which the generator can continue to operate until running out of fuel based on the detected initial fuel level and generator load characteristics. The initial estimated remaining runtime value is displayed as an indicated remaining runtime for viewing by a user. A revised runtime estimation is performed by evaluating current or updated detected values of the fuel level and generator load characteristics. A revised estimated remaining runtime value is calculated that corresponds to a time duration at which the generator can continue to operate until running out of fuel based on more recent detected current fuel level and generator load characteristics. The revised estimated remaining runtime value is displayed as the indicated remaining runtime. The indicated remaining runtime may be displayed as a numerical value, such as in a countdown time form in hours and/or minutes.
According to another aspect of the invention, a step update may be done by performing a step updated revised runtime estimation. The step updated revised runtime estimation includes identifying a step change in a value of at least one of the fuel level and generator load characteristics. The step change(s) corresponds to a change exceeding a respective threshold value indicating a relatively large change influencing an amount of time at which the generator can continue to operate until running out of fuel. This can include rapid changes in the overall generator system such as filling or siphoning the fuel tank, adding or removing an auxiliary fuel tank(s), and/or adding or removing an electrical load consuming power from the generator. When the step change is detected, the current fuel level and generator load characteristics are detected. A step updated revised estimated remaining runtime value is calculated that corresponds to the time duration at which the generator can continue to operate until running out of fuel with the new load and/or amount of fuel. The step updated revised estimated remaining runtime value is displayed as the indicated remaining runtime.
According to another aspect of the invention, a system calculates and displays an estimated remaining runtime for a portable generator. The system includes a fuel sender extending at least partially into a fuel tank of the generator. The fuel sender has a sensor arrangement configured to provide a signal corresponding to a portion of the sensor arrangement that is submerged in fuel stored in the fuel tank. A control system is operably connected to the fuel sender and configured to receive the signal from the sensor arrangement and to evaluate the signal to determine a fuel level of the fuel stored in the fuel tank. A display system is operably connected to the control system and configured to display the fuel level for viewing by a user.
According to another aspect of the invention, the sensor arrangement may have multiple capacitive sensing elements vertically stacked so that the fuel stored in the fuel tank wets respective portions of the multiple capacitive sensing elements. Wetting of the portions of the capacitive sensing elements changes capacitive characteristics so that portions submerged in fuel have different capacitance values than portions above the fuel level and thus not wetted.
According to another aspect of the invention, the fuel sender has a printed circuit board (PCB) upon which the multiple capacitive sensing elements are arranged. A cover may overlie the PCB to provide a barrier between the PCB and the fuel stored in the fuel tank. The cover can be incorporated as an encapsulating material such as conformal coat, an over mold, and/or a molded plastic housing, overlying the PCB. According to another aspect of the invention, the control system includes a microcontroller mounted to the PCB and operably connected to the multiple capacitive sensing elements.
According to another aspect of the invention, a system is provided that detects whether an auxiliary fuel tank(s) is connected to a portable generator. An onboard or main fuel tank of the portable generator and the auxiliary fuel tank(s) may each include separate fuel level sensor(s), and a control system may receive signals from each fuel level sensor. The control system may calculate the amount of fuel remaining and/or the remaining runtime based on both signals and may further evaluate generator load when determining the remaining runtime. When the auxiliary tank is connected or disconnected, the control system automatically updates information displayed such as on a generator control panel, which may provide a visual indication of both the amount of fuel remaining and the duration of the estimated remaining runtime.
According to another aspect of the invention, communication between an auxiliary fuel tank(s) and the portable generator can be established through an electrical connector arrangement that facilitates tool-less self-connection of the auxiliary tank(s) to the portable generator. The electrical connector arrangement may include a female contact portion that is recessed into and defines a pocket within a bottom wall of a housing of the generator. The female contact portion may include spring contacts extending transversely across the pocket of the female contact portion. A male contact portion may be arranged at the auxiliary fuel tank(s) and extend upwardly from a top wall of the auxiliary fuel tank(s). The male contact portion may define a generally wedge-shaped or triangular profile when viewed from a side elevation with a pair of converging angled walls to which the contacts of the male contact portion are mounted. When the female and male contact portions engage each other, the spring contacts of the female contact portion create a wiping motion along the angled walls of the male contact portion to remove debris as it is inserted into the female contact portion of the electrical connector arrangement. The spring contacts of the female contact portion also bias against the contacts of the male contact portion to establish and maintain a good electrical connection.
Other aspects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.